Lens mounting



4 Nov. 19, 1929. J. B. GRIFFITH LENS MOUNTING Filed April 13, 1927 GIIIIIII i m V in eyesight, and it com altering the strength comprise, essentially, a rotary disc which carand, consequently,

' desired in anexamination o Patented Nov. 19, 1929 1 JAMES IBEATY GRIFFITH, OF

T rm

WASHINGTON, DISTRICT or COLUMBIA Inns ivrobnrme Y Application filed A ril 13,

This invention relates to lens mounting for optical instruments, and more particularly to the mounting'of lenses in optometers and like instruments used in determining errors prises a series of lenses straight side edges, mounted in a support in abutting relation whereby the distance from the edge of each 7 lens to its center is decreased, but without and accuracy of the lenses, to thereby decrease the amount of initial prismic displacement and the-duration time of the prismic displacement.

Optometers as at present manufactured having substantially rles'a number of plus and minus spherical lensesmounted around its periphery, vSuch discs must be of relatively small. diameter in order that the instrument be notiunwieldy,

with discs of small diameter-it has been found impossible to mount more than a small number'of the lenses necessaryffor a proper examination} In the past it has been the practice to providea circular 2 disc of convenient'size with a limited number -:of separate, spaced and'uniform sized circular apertures, and to mountin such apertures a series of spherical lenses of progressively increasing strength, beginning with,

:7 0 diopter strength +1.00 or 1.00 and continuing in diopterintegers tothe desired strength for making examination,

In order to provide, between these strengths, the fractional strengths so often a second lens carrier is provided containing uniform spaced and sized apertures in which are mounted plus and minus'spherical lenses of fractions of 'a diopter strength. By pass- 0 ing these supplemental fractional power enses in front of any one of those of integralppowera secondlens strength can be produced, this strengthbeing either'greater or less than that of the integral powerlens, depending upon whether the supplemental carrier presents a plus or minus. fractional, power lensbefore the lens of integral powerv in the disc. Thus, if a +3.00 lens was found to be too weak and a +4.00 lens too. strong, the +3.00 lens would be set in the. line of defects of eyesight only at one. point, 0

successively. befor tinuity of effect i tim e is consumed mg to focus on a the line of f the human eye 7 7 confusmgand undesir.

movement, begins at the mom ceases- While it is im fully described. 7

1927. Seria1" No. 183,389.

vision of the patient and the segment moved to bring, in succession, the lenses of-fracflODEtl st-rength'into registration with those of the disc. y this procedure it' was attempted to obtain the same optical efi'e ct with a +3.00 lens and a superposed +.7 5 lens, for example, as would be produced by a +3.75 lens. Actually, however, the combined lenses have? the effect of a single lens stronger than +3. 5. I

A further disadvantage in instruments for testing and determining the condition and resides in the mounting of the circular lenses'side'by Iside'contacting r entirely separating the lenses'so that between adjacent lenses there lies a small strip of the opaque material'comprising the lens,v support. Thus," when the instrument is actuated "to bring the lenses e the patients eye theficons broken by the visual ob n the lenses, and a longer i by the patient who is try-' I distant object with the aid of the lenses as they are; successively presentedbeforehis line of vision, because the opaque areas between the respective lenses obstruct the vision and prevent a'continuous view of the objective; I With circularspherica-l lenses as haveherei toforebeen used each lens as it passes "across vision from its'edg'e to its center y give .to the observer an impression of movementof the viewed object. Thismovementis false, and to that extent is able, The movement, known as-prismatic displacement or parallex ent the edge of r the approaching lens ;intersects the li'ne'of vision, and continues, but with deoreasing speed, as the lens center is approached. 1 When the lens. center is reached the movement possible to entirely antage my, invention structions": betwee must necessaril eliminate I this disadv provides the means f0 q to a minimum, as will hereinafter be more.

' One of the objects provide a mounting eeses whereby ufli 1 of inventionis to forf spherical optical r r reduc ng such effect 7 cient number of lenses; 9

- can be mounted within a frame or support of convenient size to permit of accurate examination without the necessity of placing more than one spherical lens in the line of of such shapeand so mounted that prismaticdisplacement or parallex movement is reduced to a minimum. 1 i Y Other and further objects will be apparent from thexfollowing description and drawing, inh; 1 1 I Figure lisa plan View of an optometerdisc with lenses. mounted in its periphery in ac-' cordance with this invention;

'7 Lthe line -Figure 2 isa section takenalong the line 2- 2. of Figure 1 Figure 3 is. a sectional. view taken along B -3 of Figure I;

.Iigure i is an enlarged view of a single lens before being mounted;

, corda' ce retinascope stick provided with lenses in acwith my invention; Figure 61s a sectmnalview taken along the 'line 6. 6.of Figure .5.

. ng I YReferrmgmore, particularlyto the drawcirculari'peripheryfwith a series of intersecting cir- Openings 2.; As is, ShOWIlin Figures .2 V. and 31these openings are not of uniform- ,diameterfrom one-face of the plate'to the p other. but aresoj 3. and a are providedupon which'the' upper 4.0T I 7' cular sh-apebut is ground formed that arcuate flanges and loweredges of the lenses 5' rest.

.- Eachcof the lenses 5 is primarily of cirdown sothat the central portion, only, remains; It. may be here stated that'it is notneeessary to grind circular lenses to-therequ'ired shape, but the lenses maybeinitially formed in the shape required, and, without subsequent operations upon, them, inserted into the frame or disc fin; whichthey are j finally and" permanently mountedi I r 1 ,11 finished condition each lens has arcuately', curved upper and lower edges and straight, sub tantially parallel side edges which areadapted to contact throughout their 7 length with the corresponding edges of adjacent lenses. shown in Figure 1, wherein,

. of kiascopes or retinascope sticks Wit-h a mounting such as 1s placed invcircular series,,the side edges of the lenses arellno't as. radii of the circle which theydefine.

In. practi e,

to the mounting of lenses in optometers,.

optical instruments.

' but inasmuch as fusion as to quent loss of time is likely Eigure 5: is :aplan view ofa skiascope or a shape heretofore described I ofmoderate and convenient. length to provided adjacent its qdrawing has lenses to'hold the stick before the eye. If for any reason plus lenses; are required for it is only necessary to thelenses are' parallel, but are formed my invention is notlrestri'ct'ed the. manner herebut may be 1 and other Retinascope sticks have heretofore been provided with either positive or negative lenses, but so far as I am aware no previous construction has embodied both positive and negative lenses in one instrument. In their use the examination of'the eye is conducted in a dark room, and both positive and negative lenses must be accessible to the examiner, the separate sets of lenses are mounted.indiiferentsticks or holders conthe identity of each, and conseto result. Furthermore,retinasco e sticks such as are used at the present time ave lenses onlyin steps ofintegers, as for example, 1.00, +2.00, and +3.0,0d' and 1.00', -2.00, -3.00d, and lenses of fractional power must besuperposed upon lenses of the am enabled to them in a stick 7 permit of; accurate examination without the use of -I- auxiliary or supplementary" lenses, whereas, as has been pointed out, lenses of fractional power have heretofore been carried-'by-a slide and. adjusted to register successively with those ofi'unit power. I amenabled to mount mount a sufficient number of sary to correct fault-finqthe vision'of the pa- ,tient.

The stick shown I 5 "mounted in two parallel rows. The lenses of one row are plus lenses while those-in theother row are minusin character. In operation, it is only necessary before the-eye of the patient and move it to bring the lenses, in succession, the minus arepresented first and the examination,

turn'the stick over and lenses, for example,

repeat the single, simple operation. 7 Fromthe foregoing it will be apparent that I have provided a mounting for lenses to be used inthe examination ofthe .eye, which mounting is simple, and inexpensive, and which permits of the ment without the use of elements; which 1 in a slide,

mounting of all necessary lenses for examination 1n ;a s ngle elemaking an 7 eliminates visualdi turbancesby dispensing with opaque framework between adjacent 100 lenses of bothifractional and unit'diopters I lenses, and which reduces prismatic displacement or arallex movement to a minimum.

What claim as my invention is:

1. An instrument for examining the eye comprising a lens support having a plurality of zonoid lenses of different diopter power mounted therein with straight side edges, the side edges of said lenses being in immediate juxtaposition whereby in a support of convenient size a series of optical lenses may be mounted, each lens differing in strength from those adjacent to it by any desired fraction out their length whereb sired fraction of a diop of a diopter.

2. An optical instrument for examining the eye comprising a support formed with a series of intersecting openings .for the reception of spherical lenses, a plurality of lenses of dif ferent diopter power mounted in the openings provided therefor, ing straight side edges contacting the corresponding edges of adjacent lenses throughsaid lenses each havy in a support of con 

